Processing apparatus



D L O N R A P PROCESSING APPARATUS 1 mm l f R Y Y t J O m E m mw: Nm@ amg/nm@ n Sm mw M m 0mm @mm m\ .w 7M o Mm e I. we A m s N, NN# wmd mmd l m mm llll Il #l |||||l||l lllllllmlll I2|| l |||||l||| nw-H. L l .Nv mg mm .WIIIII HIJ! NNN mJT m- N m \7ON w :n lllllllmmmrw 4 I llldnullll llll Il LH w 4 /r mi @d u Q 4 w u o la nv n D f w ONM -Nm mm .Wm l 0 .M n m 10, 16 P. ARNOLD PROCESSING APPARATUS 4 Sheets-Sheet 2 Filed Dec. 4, 1957 2?@ IZIQTOR ATTO R N EY May 10, 1960 P. ARNOLD PROCESSING APPARATUS Filed Dec. 4, 1957 4 Sheets-Sheet 3 INVENTOR @MFI www ATTORNEYS.

Pill-..- /29 W9 1960 P. ARNQLD PROCESSING APPARATUS 4 Sheets-Sheet 4 Filed Dec. 4, 1957 fit This invention relates to processing apparatus, in which workpieces are automatically transported to successive stations, where they undergo different treatments in a sequence. More particularly, the invention is concerned with an apparatus of the type described, which is provided with novel means for effecting modifications in the treatments given selected workpieces. The apparatus of thel invention may be used for various purposes, but since all the advantages of the invention are realized ini-its application to electroplating, an `apparatus suitable for such use and embodying the invention will be illustrated and described in detail for purposes of explanation.

Automatic electroplating apparatus commonly includes a plating machine having a plurality of preparation tanks for cleaning, rinsing, etching, and like treatments, one or more plating tanks, vwhich usually have va plurality of plating stations, and `a plurality of linishing tanks for reclaim, hot and cold rinsing, etc. ln one common form of such apparatus, the workpieces are handled by being mounted in groups on carriers, such as racks, and, in the plating operation, the racks are hung from arms on a processing conveyor, Vwhich extends along the tanks and advances the racks stepwise one tank or station at a time.

Patented May 10, 1960 racks hung from the respective arms. While the Curtis i apparatus functions satisfactorily, the elements von the conveyorrarms, must be set manually in accordance with the kind of workpieces carriedA by the arms and the adjustment of the elements is diticult to carry out while the conveyor is in operation and requires the services of an alert skilled Vworkman at the transfer station.

The present invention is directed to the provision of a processing apparatus for subjecting workpieces on racks to Ia series of treatments, which is provided with means for modifyingthe treatments given to the workpieces on selected racks and in which the treatment to be given the workpieces on any rack can be determined by the workman who loads the racks or by another person located remotely lfrom the processing conveyor. The new ap- Yparatus thus achieves the desired result without the services of an alert or highly trained workman at the transfer station.

` The new apparatus includes a processing machine with a conveyorfa'nd elevator for transporting workpiece racks to Vandremoving them from treating stations, a transfer stationwhere the racks of work aredelivered to. and

received' from the machine conveyor, and a second conveyor between the transfer station and a station for loading and unloading the racks. The machine is provided with means for modifying Vthe treatments ordinarily given the workpieces and the modifying means may produce y any of a number of effects, such, for example, as apply- An'elevator extends over the tanks, where the racks must L ing a plating of less than usual weight, varying the cur- Y rent density in certain plating cells, subjecting workpieces to special sprays, skipping certain cells, etc. In order to actuate the modifying means selectively, the machine con- Y veyor is provided with elements, which aredisposed adjacent the Vsupports for respective racks on the conveyor moves in timed relation to the movement of the proc'- essing conveyor. and advances the racks to a transfer station. ln each period of rest of the conveyors, a rack of raw work at the transfer station is delivered, manually or by a suitable transfer mechanism, from the monorail conveyor to the processing conveyor and a rack of finished work is removed from the. processing conveyor and placed on the monorail conveyor. The. racks of finished work Aare then moved by the monorail conveyor to an unloading station, where the racksA are unloaded, after which the empty racksare moved to the loading station and the cycle of operations is repeated.

In the operation of suchelectroplating apparatus, it

frequently happens that the workpieces `areof two or' more kinds requiring different treatments, as, for example, some of the workpieces may require -a heavier plating than others. Such a dilference in plating may be achieved in' various ways and one expedient involves causing the racks of workpieces, which are to be given a light plating, to be held out of the plating tank for a part of the length thereof by such means as are` disclosed in Curtis and can beset to render selected modifying means eective as the conveyor advances. The setting of the elements is accomplished by means operabley selectively by members on parts of the second conveyor and the construction is such that, when 4a workman places a rack of raw workpieces on the second conveyor, he adjusts the members on parts of the second conveyor adjacent the rack support to produce the treatment modifications desired for such workpieces. As the rack approaches the transfer station, the support Yon the machine conveyor, on

which the rack is to be placed, is approaching the place t where/it will receive the/rack and, during such approaching movements, the operative members on the second con- Parent 2,605,882, issued August 5, 1952. The Curtis apparatus includes a processing conveyor with arms raised and lowered by an elevator andA a: selectively operable device is mounted at each plating position to be bypassed and acts to prevent a conveyor arm from being lowered by the elevator at such position. The devices are operated by elements, such as cams or tabs, which are mounted on the conveyor arms and are set to actuate thedevices or to leave them inoperative, dependingon the kind of :Platingto be -given the workpieces on the veyor actuatemeans for setting corresponding elements on the machine conveyor adjacent the rack support there on. `When the rack has been transferred to the machine conveyor and is moved through the machine, the selected elements operate their related modifying means so that theworkpieces on the rack are given modifications of the usual treatments. Y

For-abetter understanding of the invention, reference Y may be-'made to the accompanying drawings, in which- Fig. 1 is a diagrammatic plan view of fan` electro-l` plating apparatus embodying the inventiong' Fig'. 2 is a sectional View on the line 2 2 of Fig. l; f Fig. 3 is a sectional view Von the line 3 3 of Fig. 2;.

Fig. 4 is a sectional viewfon" the lineY 4 4 of Fig. l,

`Fig. 5 is a fragmentary vertical sectional view onan enlarged scale of the triggers for operating the treatment modifying means; l

Fig. 6 isfa Aplan View of the group of triggers; u

Figs. 7, 8, and 9, are sectional viewspon the lines.7 7,'j

A 8 8, 9 9, respectively, of Fig. 1;

Fig. l0. is a sectional view on the liner10`16j of Fig. 9;

Fig. 1l is a vertical sectional view illustrating one.H form of'elevator ipper, which maybe usedin' the. apparatus;

3 Fig.- l2 is a view of a bridge, which may be employed with the elevator;

Fig 13 is a wiring diagram of a circuit for varying the current density in a treatment cell; and

Fig. 14 is a perspective view of a modifiedy featured ofthe apparatus; Y

The electroplating apparatus illustrated in Fig. l comprises a series of stations disposed alongan'endless conveyor indicated' at 2l). The conveyor hasA f parallel stretches connected lbycurved end portions and' arrelevator structure is Adisposed within the conveyor and includes beams 21, 22 extending alongthe parallel stretches ofthe conveyor. At one end of the conveyor, the elevator has a curved beam 23 connecting the stretches321, 22

while, at the other end, there is a xed track 24. The conveyor advances stepwise and, in each period of rest betweenv successive conveyor movements, the elevator moves down and then rises to its 11p-position. y,

A` group of treatment tanks 25, 26, 27, 28 lie at respective stations along the stretch of the conveyor adjacent the elevator beam 21 and the tanks maybe employed .for preplating treatments such as cleaning, etching, etc. The apparatus illustrated includes a cell 29 in which an electrolytic treatment is carried on and the cell contains,

one or more anodes indicated diagrammatically in Fig. 13 at 29a. each step in the conveyor movement hasalength equal tothe spacing between the centers of the adjacent tanks. Beyond tank 29, there is treatment tank 30 of unit size disposed atthe'curved end of the conveyor, and, at the Ibeginning of the second stretch of the conveyor, there is a plating tank 3i., which is of multiple unit size and, in

the apparatus shown, has a length equall to that of four unit tanks. Tanks 32, 33, 34 for post-plating treatments are disposed beyond the plating tankrand are of unit size'.

The `convey-or may be of dierent types,l but that.`

shownv comprises upper and lower chains 35 (Figs. 4, 7, ll), provided with rollers 35a running in channels.36 on the machine frame. The chains are connectedatintervalsequal to the unit tank spacing by pairs of vertical guidesV 37, between which are mounted skate-like slides' 38 having rollers 38a running in the guides. Each slide has an arm 39 which extends out over the tanks and is provided witha hook 39a or like means, from which a workpiece carrier, such as a rack 40 with a hook40a, may be suspended. Each slide 38 is provided at the rear with a pick-up roller 41 and each of the elevator beams has an angle iron 42 serving as a track, on which the roller 41 may run. Each slide is also provided with a hold-out roller 43 at its front.

The racks 40 are loaded with raw workpieces at a loading station 44 disposed along one stretch of a loadfA ing conveyor 45, which may be of the monorail type and` have carriages 46 provided with hooks 46a for engagement with the hooks 40a of the-racks. The raw work is supplied to the loading station by a plant conveyor 47 of any suitable type. The racks of finished work are removed from the conveyor 45 at an unloading station 48 and the iinished workpieces are carriedv away onY a plant conveyor` 49.. conveyor 45 and the conveyors 47 and 49 may be part of a single,V plant conveyor system. A siding 50may be installedV to extend between the loading and unloading stations and provide means for transferringr theracks emptied at the vunloading station to the loading station.

The conveyor 45 has a stretch lying parallelto one.

stretch of. the .processing conveyor` 20, and a; transfer mechanismTM of conventional construction is advantageously provided at a transfer station located between the parallel stretches of the conveyors. The conveyors 20 and 45 move stepwise substantially in synchronism in oppositedirectionsand the steps in the movements of the two conveyors are of the same length. ConveyorA 45`is so constructed that successive stations, at which- The tanks 25-29, inclu., are of unit size and' AIn some installations the loadingl fer station.

carriages on the conveyor come to rest at one end of the transfer mechanism, lie opposite successive stations, at which arms on conveyor 20 come to rest. Accordingly, in the operation of the apparatus, the transfer mechanism may act in each period of rest of the conveyors to transfer a rack-vof raw work from a carriage on conveyor 45 to an arm on conveyor 20 and to transfer.` a rackof finished work from an arm on conveyor 20fto a carriage on conveyor 45. In some cases the transfer mechanism may be omitted and a workman may perform the task of transferring the racks of workpieces during periods when the conveyors are at rest.

The apparatus illustrated includes means for modifying three of the treatments, to which the workpieces are ordinarly su.bjected, and, by way ofV example only, one modication involves a change in the currentdensity in cell 29, a second'rnodiiication involves subjecting workpieces 1 to less than normal plating treatment, while the third modification consists of the use of sprays 32a in tank 32. In order to operate thevmodifying means selectively, each carriage 46 on the conveyor 45 is provided with a set of tabs 51 pivotally mounted thereon and movable to operative positions at right angles to the direction of moveinoperative position by suitable detent means, for example. The individual tabs 51a, 51b, and 51e-are, disposed one above the other (Fig. v2) and, as eachcarriage moves to the irst station in alignment withv the transfer station, it passes a group of limit switches LS1, LSZ, LS3 mounted on a bracket 52 attachedl to a part of the ma.- chine framework. The limit switches have operating shafts 53 extending vertically therefrom and carrying respective laterally extending rods 53a, 53b, 53C, and the.

shafts of the switches are of different lengths, so that vthe rods lieV at different levels and are engageable byl respective 'tabs 51a, 51]), 51C in operative position.

The conveyor 20 is provided with a set ofV triggers 54, 55, V56 adjacent each arm 39 and the triggers of'each set may be mounted on a plate 57 attached to one of' the guides 37 for theslide, on which the arm is mounted. Each trigger consists of a bell-crank lever attached/to a collar 58 pivotally mountedA on a rod 59 attached to plate 57 and the collar of each trigger has a pair of springpressed detents 60, 61 adapted to enterv notches in rod 59 and hold the triggers in one or the other of'l'two positions. When the detent 60 of a trigger, for example, theftrigger 54, lies within its notch in rod 59, the trigger 1s 1n inactive position (Fig. 5) land its arm 54a lies against a rod 62 carried by the plate 57. When the trigger has been moved angularly to cause its detent 61 to enter the corresponding notch in rod 59, the trigger is in active position and the arm 54a of the trigger extends vertically, while the arm 5411 extends horizontally and ylies on top of a rod 63 carried by a plate 57. The vertical alms 54a, 55a, 56a of triggers 54, S5, 56 are of gradually decreasing length and arm 55a has a laterally extending tab 55C at its upper end, while arm 56a has a vices which are mounted on a part of the machine frame-V work and may be solenoids S1, S2, S3, hydraulic or air cylinders, etc. At that time, a carriage 46 on conveyor 45v loaded with a rack of raw work is passing the limit switchesrLSLLSZ, LS3 and is about to stop at the trans'- The limit switches control the energization of respective solenoids and, as the carriager passes the limitswtches, the tabs on the carriage, which have been moved to operative position, operate their associated'- limitv switches to energize the corresponding'k push-pull` solenoids;y Upon energization of-a solenoid, its plungery moves; to strikethe arm` of a: trigger and moves the'latd ter angularly to operative position. Accordingly, when the rack of workpieces is transferred from-the carriage 46 on conveyor 45 to the arm 39 on conveyor 20, the triggers associated with the arm are selectively moved to operating position as determined by the setting of the tabs 51 on the carriage.

Ater an arm 39 on the conveyor 20 has received a rack of workpieces, it is advanced by the conveyor to the successive tanks 25, 26, 27, 28 and 29. As the arm comes to rest at each tank, it is lowered by the elevator to immerse the workpieces in the solution in the tank and is then raised for the next advance by the conveyor. A normally open limit switch LS4 is mounted adjacent the path of an arm 39 being moved by the conveyor from tank 28 to tank 29 and, yif the appropriate trigger on the arm has been moved to operative position, it causes the limit switch LS4 to be closed as the armpasses the limit switch. The limit switch LS4 lies in a circuit (Fig. 13) between power lines L1, L2 and, when the limit switch is closed by a trigger, current flows between the lines to energize a solenoid relay S4, which establishes a holding circuit'for the solenoid, containing the normally closed limit switch LSS. The energization of solenoid S4 also opens a circuit around a resistance R between line L1 and the anode 29a in tank 2.9.v rThe workpieces on the rack 40 in the tank are connected to line L2 and, when the circuit around resistance R is opened, a reduction in the density of the current flowing through the tank between the anode and workpieces results.

When the rack Vis raised from tank 29 and advanced beyond the tank, the trigger yon the arm 39, which closed the limit switch LS4, opens the limit switch L85. The solenoid S4 is thereupon de-energized and the circuit around the resistance R is closed, 4so that the conditions for the passage of current at normal density through cell 29 are again established.

The modification in the length of the plating treatment given selected workpieces can be accomplished in different ways and, in the apparatus shown, the racks of workpieces, which are to receive a light plating, are advanced along half the length of rthe plating tank before being lowered to immerse the workpieces in the plating solution. can be obtained in other ways and the late' set-down of the workpieces is merely typical. t

In order to plate the workpieces selectively, the track 42 on elevator beam 22 has an opening at the iirst plating station in tank 31 and a ilipper 64 is pivotally mounted in the opening and is normally held by a spring 65 to close the opening and complete the track. A springpressed plunger `66 is mounted on the machine frame near the lowered position of arm 39 at the platingstation and, when the arm has been moved down, the plunger acts to tilt the ilipper, so that the elevator can rise with the ipper missing the roller 41 on the slide of the arm. The ipper is thus active in the up position of the elevator to support an arm, whose roller moves on to the ilipper, but the flipper always leaves the -arm in down position.

A hold-out plate 67 is mounted in line with arm 39 on conveyor 20 at the iirst plating station of tank 31, and the plate is attached .to the lower end of the arm 68 depending from one end of lever 69. The other end of the lever is pivoted on a standard 70 rising from a bracket 71 attached to the machine framework and leverV 69 yis attached between its ends to the plunger 72 of a push-pull device, such as a solenoid S5, which can be energized by closing of a limit switch LS6. The rod 68 is encircled near its upper end by a spring 73 and, when the solenoid SS is deenergized, the spring raises rod 68 so that the plate 67 lies abovethe hold-out roll'er 43 on the arm 39. When an arm carrying workpieces, which are to be given half the normal plating treatment, approaches the plating tankV 31, the `appropriate trigger on the arm will have been set to 'operate limit switch L56. Operation of the It is to be understood that thev same result switch causes the solenoid S5 to be energized and plate 67 is moved toits down position, so that, as the arm approaches the first plating station of tank 31, its auxiliary roller 43 rolls on -top of the plate 67. Thereafter, when the elevator moves down, the arm 39 is held in upper position by its roller 43 resting on the plate. Upon the ascent of the elevator and the next forward movement of the conveyor, the arm 39 is advanced along the elevator track to the second plating station in the tank. In such movement, the trigger on the arm, which operates LS6 to cause energization 'of solenoid S5, operates a limit switch LS7 and causes the solenoid to be de-energized.

At the second plating station of tank 31, the elevator track has an opening, which is normally closed in the up position of the elevator by a bridge comprising a plate '74 mounted on a pair of rods 75 attached to the machine framework and urged to downward position by springs 76 encircling the rods. When an arm 39 is advanced along the raised elevator track 42 to the second plating station of tank 31, the roller 41 of the slide of the arm rolls upon the plate 74 and, when the elevator is lowered, the arm remains in the up position. Upon the next advance of the conveyor, the arm is moved to the third plating station of tank 31, at which point the arm is to be lowered to immerse the workpieces thereon in the solution. At the third plating station, the elevator track has an opening, in which is mounted a ilipper similar to flipper 64, and, when an arm rests upon the ipper, the arm is lowered when the elevator moves down. In the down position of the elevator, the flipper -is operatedby a spring-pressed plunger similar Yto plunger 66, so that the flipper is made inactive and cannot pick up the lowered arm when the elevator next rises. The arm in the down position is movable on a rail extending along the top of tank 31, and, when the elevator has reached its up position, the arm resting on the rail is moved tothe last station in tank 31. At this station, the elevator rail has an' opening `in which is mounted a flipper similar to ipper 64 and normally held closed by a spring. When an arm 39 has been moved along the tank rail to the last plating station in the tank and the elevator is lowered, the pper engages the roller 41 on the slide ofthe arm and is swung so as to pass by the roller and then swings back into position beneath it. Upon the next ascent of :the elevator, the arm is raised from the plating station and is ready for advance by the conveyor to tank 32.

In the operation of the apparatus, the triggers of arms carrying workpieces, which are to receive a full plating treatment, are not set to active position lby the solenoid S2. Accordingly, when such an arm is advanced along the elevator track to the rst plating station in tank 31, the limit switch LS6 is not operated,so that the hold-out plate 67 remains in the `up or inactive position. When the elevator descends, the arm is lowered with it, because the roller 41 of the slide of the arm rests upon ipper 64. When the arm comes to rest on the tank rail and the elevator rises, the ipper is operated by plunger 66 to miss the roller 41 and leave the arm. Upon the next advance of the conveyor, the arm is moved along .the

tank rail to the second plating position in the tank and, since the elevator track has an opening at this point,"

the elevator can not raise the arm at this position. Whenthe arm is moved along the tank rail to the third plating position, the arm is in line with 'a ilipper on the elevator, which is similar to llipper y64 and is made inactive in its down position `by a spring-pressed plunger. Accordingly,

when the elevator rises, the ipper leaves the arm behind. The arm is then advanced along the tank rail to the last plating position in tank 31, from which it is raised lby an elevator flipper in the same manner as an rarm low-r ered to the tank at the third plating position.

Tank 32 is the rst of the ,nishing treatment tanks and i-t is provided with spray nozzles 32a by which a suitable liquid may be sprayed upon workpieces carried by an 1 armat the tank. The operation of the nozzles is con# t trolled by a trigger on each arm and the operation of the nozzles is initiated by operation of limit 'switch LSS by he trigger and is terminated when the trigger operates limit switch LS9. If it is desired to skipv one or more of the tanks or cells, the machine may be provided, atappropriate places, with hold-out plates of the type shown in Figs. 9 and 10. Limit switches, at suitable locations, would be actuated by triggers on the arms 39, in the manner described, to lower the hold-out plates adjacent tanks to be skipped. Skipping of particular tanks is frequently desirable in multiple electroplating or anodizing and dyeing operations, for example.

After leaving tank 32, the arms are advanced to tanks 33, 34 and finally arrive at the station of the transfer mechanism, which operates to transfer workpiece carriers from conveyor 20 to conveyor 45. In the movement of the arms past tank 34, the horizontal arms of active'triggers on the arms ride up the surface of a fixed cam 77 and the triggers are restored to inactive position. The tabs 51 may be reset automatically to inoperative positions by means of a striker bar 77a mounted adjacent the conveyor 4S, in the path of-movement of the tabs on conveyor carriages 46 leaving the transfer station as the carriages 46 move past the bar 77a, all of the tabs are moved to inoperative positions. When the carriages are later reloaded with racks of raw Workpieces the tabs 51 may beset selectively in operative position, in accordance with the schedule treatment for the workpieces.

In the apparatus so far described, the carriages on conveyor 45 are provided with tabs 51, which can be set to operate switches which control the action of the solenoids or other push-pull devices setting the triggers on the conveyor 20. Instead of using limit switches foractuating the solenoids, photoelectric means may be employed and a simple form of such a control for a single push-pull device is illustrated in Fig. 14. When a photoelectric control is employed, the carriages 46' on conveyor 45 are provided with a pivoted llag 78 adapted to be swung from an inactive horizontal positionrto an active vertical position. A lamp 79 is mounted'at one side of the plane of movement of the carriages `46 and in the approximate location of the limit switches LS1, LS2, LS3 and the lamp is carried by a bracket 80, which also supports a photoelectric cell 81 aligned with the lamp and at the opposite side of the plane of movement of carriages 46. When aV carriage with a load of workpieces, which are to `be subjected to the modified form of treatment, approaches the transfer station where the workpieces are to be transferred to an arm on conveyor 20, the flag 78' on the carriage, in its active position, breaks the beam directed by lamp 79 on photocell 81. This causes an energization of a push-pull device which sets a trigger on the arm on conveyor 20, to which the workpieces on carriage 46 are to be transferred, and the trigger then operates the modifying means at the proper time.

It will be apparent from the foregoing that the new processing aparatus provides remote control means by which selected workpieces being advanced by the processling conveyor 20 may be given modified treatments by the action of triggers on the arms supporting the workpieces. The triggers are set by the tabs on the carriages on conveyor 45 and theV tabs can thus be selectively adjusted by the workman loading the carriages or at some other place remote from the processing conveyor.

Substantial advantages are realized with `the new apparatus, in that in many cases a workman, otherwise required at the transfer station, may be replaced by an automatic transfer mechanism and, in cases where a workman is used at the transfer station, a semi-skilled or unskilled man can handle the jobsatisfactorily.

While the invention has been described in connection with its embodiment in an electroplating system, it will be understood that the invention has advantageous application to a wide variety of processes and apparatus, in

which selective treatment is given to workpieces. By way of example only, and not of limitation, the invention may be used to advantage in systems for multiple electroplating, anodizing with selective dye bath, phosphating, bonderizing, bonderlubing, pickling, lacquering or enameling, galvanizing, cleaning, electroforming, printed circuit deposition, etching, and the like. And it will be understood that the foregoing and other operations may be carried out singly or in various desired combinations.

I claim:

1. An apparatus for performing a series of operations on a succession of articles, which comprises a plurality of racks for the articles, a plurality of stations, means at respective stations for giving the articles different treatments, means for modifying the action of the several treating means, a processing conveyor having parts engaging and moving the racks stepwise along the stations, elements on the processing conveyor settable to operate selected modifying means as the processing conveyor advances, elevating means operating in timed relation to the processing conveyor and moving the racks vertically into and out of the stations, a transfer station, at which racks are loaded on and' unloaded from the processing conveyor, conveying means having parts for delivering racks ,to and receiving them from the transfer station, members on said parts of the conveying means corresponding to respective modifying means and movable into and out of opertaive position, and means adjacent the transfer station and actuated by an operative member on a part of the conveying means delivering a rack to the station to set an element on the processing conveyor to cause said element to operate a selected modifying means.

`2. The apparatus of claim l, which includes an automatic transfer mechanism at the transfer station for loading racks on and removing them from the processing conveyor.

3. The apparatus of claim 1, which includes means for restoring the elements to initial condition after they have acted on the modifying means.

4. The apparatus of claim 1, which includes means for restoring the members to initial condition after they have acted on the element setting means.

5. The apparatus of claim l, in which the elements on the processing conveyor are set by push-pull means and Ithe modifying means are operated by switches actuated by the elements.

6. The apparatus of claim 1, in which the elements are set by push-pull means to operate selected modifying means and the push-pull means are operated by the members on the conveying means.

7. The apparatus of claim l, in which the conveying means has carriages for delivering racks to and receiving Vthem from the transfer station and the members are movably mountedon the carriages.

8. The apparatus of claim 1, in which the processing conveyor has arms for supporting the racks, the means for modifying the action of the treating means, include switches controlling respective modifying means, and the elements are mounted on the processing conveyor adjacentV respective arms thereon.

9. The apparatus of claim 1, in which the means actuated to set an element include photoelectric means vhaving beams broken by members in operative positions.

l0. The apparatus of claim l, in which the processing conveyor has arms for supporting the racks, the arms are movable in guides, and the elements are mounted on the guides for respective arms.

References Cited in the file of this patent UNITED STATES PATENTS Finston Oct. 20, 1942 2,716,415 Davis et al. Aug. 30, 1955 

